1. Field of the Invention
The present invention relates generally to contact arrangements for electrical apparatus and more particularly to an arrangement where first and second contact portions of a moving contact assembly are arranged to efficiently and consecutively engage respective first and second stationary contacts.
2. Description of the Related Art
Various contact arrangements are provided for electrical apparatus such as switches to achieve desired contact engagement and electrical circuit connections. For example, U.S. Pat. Nos. 3,588,406 and 4,695,918 are directed to contact arrangements where a electrical component is inserted into the circuit prior to the engagement of the main contacts of the switch. Other contact arrangements, for example as shown in U.S. Pat. Nos. 3,787,651 and 4,107,487, connect a shunt contact path in parallel with a main contact path such that the shunt contact path is established prior to the opening of the main contacts; circuit interruption being accomplished via the shunt path after the main contacts have achieved a predetermined degree of separation. The contact arrangement of U.S. Pat. No. 3,787,651 also includes arcing contacts which are engaged prior to the engagement of the stationary main contact by the blade that carries the shunt and arcing contacts. A variation of this arcing contact arrangement is shown at page 12 of S&C Electric Company Descriptive Bulletin 761-30, dated Apr. 16, 1984. Another type of contact arrangement shown in U.S. Pat. No. 5,013,876 utilizes the orientation and configuration of two contacts to provide different areas of engagement of the contact surfaces as the contacts move into engagement, i.e. from initial contact to the closed position.
While the prior art arrangements are generally useful to provide predetermined specific contact engagement between various contacts, it would be desirable to provide a more efficient contact arrangement to efficiently achieve the consecutive engagement of two stationary contacts, especially where the moving contact also rotates as it moves between the open and closed positions.